The North's political parties were under increasing pressure today to agree a deal to save the region's power-sharing government.
After more than a week of round-the-clock negotiations on policing, justice and parades, Taoiseach Brian Cowen and British Prime Minister Gordon Brown have been on standby to arrive to put their seal on a final agreement.
But plans to unveil a deal on Monday were scuppered after a significant number of Democratic Unionist Party (DUP) members refused to back the proposals in a private briefing from their leader Peter Robinson.
Negotiations have since been resumed in Hillsborough Castle, Co Down, between the DUP, Sinn Féin and the Irish and British governments, with the focus now on whether Mr Robinson can secure a package his party can back.
It was claimed that up to 40% of DUP Assembly members refused to back the blueprint, with dissatisfaction over arrangements for overseeing controversial Orange Order parades high on the list of concerns.
But DUP deputy leader Nigel Dodds said: "Despite the speculation and innuendo being peddled by unidentified sources and some sections of the media, the DUP Assembly Group has endorsed the work of our negotiating team and has given its unanimous support to the DUP leadership to continue working on the outstanding issues."
He added: "Peter is a first class unionist leader and enjoys the full support of the party."
A deal is expected to cover the devolution of policing and justice powers from Westminster to the Assembly by May, a key republican demand, plus new arrangements on overseeing loyal order parades, which is sought by unionists.
Sinn Féin and the Democratic Unionist leaders briefed their Assembly groups at Stormont again yesterday and should also do so today, but there were predictions last night that the search for agreement could continue until at least Thursday.
Sinn Féin Assembly member Alex Maskey said there were some outstanding issues.
"We would not be talking at Hillsborough or anywhere else if we didn't believe that there was a prospect of getting a positive outcome," he said. "We believe there is a prospect of getting a deal, we are there to get that."
SDLP leader Mark Durkan drew parallels between the current DUP difficulties and an earlier period of the peace process when the then Ulster Unionist Party (UUP) leader David Trimble faced constant pressure from hardliners in his party who opposed dealing with republicans. The subsequent tensions were seen by many to have eventually weakened Mr Trimble's hand.
"Some of these issues are being treated as if they are the private property of the DUP and some of its more doubting members at that," said Mr Durkan of the current talks.
"It is not the best of way doing things, leaving things resting on the opinions of a few people inside one party.
"We had that problem earlier in this peace process, with things centring on some of the doubters and dissidents within the UUP, and the questions always being asked whether Trimble would prevail against some of their doubts and tactics. We don't want to be back into that sort of syndrome."
But East Derry DUP MP Gregory Campbell, often identified as a party sceptic wary of a deal with republicans, said the DUP enjoyed a "healthy debate" over a range of issues within the Assembly group.
"The party is united in its determination to get the best deal for not just the unionist community and of course for Northern Ireland as a whole but to ensure that it is a durable deal, that remains our focus."
Ulster Unionist leader Reg Empey said if a DUP/Sinn Féin deal was agreed his party would consider its contents before deciding its position, but he warned that the public was becoming increasingly disenchanted with the length of time it was taking to seal a deal.
Empey said: "It is hugely embarrassing to the Government, hugely embarrassing to the Prime Minister and I think it is hugely embarrassing for Northern Ireland."
During the lengthy process it has emerged that the Ulster Unionists, which already have an electoral alliance with the Conservative Party, conducted secret talks with the DUP about promoting greater pro-union co-operation in Assembly.
The behind-closed-doors exchanges prompted speculation of a possible merger in a bid to thwart Sinn Féin attempts to become the largest party in the North.
But last night Empey ruled out a formal link up.
At a meeting of his party's executive, he dismissed talk of a formal link up.
"I can categorically say that rumours of a merger with the DUP are untrue," he said.
"No deal has been agreed and no formal link with the party has been made."
He confirmed that discussions had taken place over the proposed upcoming Assembly election but stressed that no commitments were made.
"I make no apology for discussing issues which look at how to best secure the future of political institutions in Northern Ireland," he said.
The UUP executive also reaffirmed its commitment to its relationship with the Conservative Party, passing a resolution to agree joint candidates for the forthcoming general election as soon as possible.